A revised introduction to aeolian geomorphology written by noted experts in the field

The new, revised and updated edition ofAeolian Geomorphology offers a concise and highly accessible introduction to the subject. The text covers the topics of deserts and coastlines, as well as periglacial and planetary landforms. The authors review the range of aeolian characteristics that include soil erosion and its consequences, continental scale dust storms, sand dunes and loess.Aeolian Geomorphologyexplores the importance of aeolian processes in the past, and the application of knowledge about aeolian geomorphology in environmental management.

The new edition includes contributions from eighteen experts from four continents. All the chapters demonstrate huge advances in observation, measurement and mathematical modelling. For example, the chapter on sand seas shows the impact of greatly enhanced and accessible remote sensing and the chapter on active dunes clearly demonstrates the impact of improvements in field techniques. Other examples reveal the power of greatly improved laboratory techniques. This important text:

Written for students and professionals in the field,Aeolian Geomorphology provides a comprehensive introduction to the topic in twelve new chapters with contributions from noted experts in the field.

Ian Livingstone is Professor of Physical Geography and Head of the Graduate School, University of Northampton, UK.

Andrew Warren is an Emeritus Professor of Geography at University College London, UK.

List of Contributors xi

Preface xiii

1 Global Frameworks for Aeolian Geomorphology1
Andrew Warren

1.1 Introduction 1

1.2 Wind 1

1.2.1 Wind Systems with Daily Rhythm and Local Scale 1

1.2.1.1 Dust Devils 1

1.2.1.2 Haboobs 1

1.2.1.3 LowLevel Jets 4

1.2.1.4 Sea Breezes 4

1.2.1.5 Hurricanes, Cyclones, Typhoons 5

1.2.1.6 Mountain Winds 7

1.2.2 Wind Systems with Annual Rhythms and SemiGlobal Scale 8

1.2.2.1 Westerlies 8

1.2.2.2 The Trade Winds 11

1.2.2.3 The Harmattan 12

1.2.2.4 Monsoons 12

1.2.3 The Calmer Globe 13

1.3 Rhythms of Erosivity and Erodibility from the SemiDecadal to Hundreds of Thousands of Years 13

1.3.1 Multiannual Rhythms 13

1.3.2 CenturyScale Rhythms 13

1.3.3 OrbitallyForced Rhythms 13

1.4 Frameworks of Sedimentary Supply 16

1.4.1 Hard Rock 16

1.4.2 Sand (632000 m) 16

1.4.2.1 The Fluvial Origins of Most Quartz Sand 18

1.4.3 Coarse Dust (1063 m) 18

1.4.4 Fine Dust (<10 m) 18

1.5 PlateTectonic Frameworks: A Glimpse 19

1.6 Conclusion 20

Acknowledgements 20

Note 20

Further Reading 20

References 20

2 Grains in Motion27
Andreas C.W. Baas

2.1 Introduction 27

2.2 The Nature of Wind 27

2.2.1 Turbulent Boundary Layers 27

2.2.2 Turbulence and Coherent Flow Structures 30

2.3 Transport Modes 31

2.4 Ripples 32

2.5 Initiation of Grain Motion 33

2.5.1 Thresholds 33

2.5.2 Grain Size Control and Dust Emission 35

2.5.3 Other Sedimentary Controls 36

2.6 Sand Transport: SteadyState 36

2.6.1 Saltation Trajectories 36

2.6.2 The Vertical Profile 38

2.6.3 Modification of the Wind 39

2.6.4 Bulk Transport Models 40

2.7 Sand Transport: Natural Environments 44

2.7.1 Fetch and Saturation 45

2.7.2 SpatioTemporal Variability 46

2.7.3 Slope 47

2.7.4 Vegetation 48

2.7.5 Sand Roses 50

2.8 Conclusion 51

Further Reading 51

References 52

3 Wind Erosion61
Jasper Knight

3.1 Introduction 61

3.2 The Processes of Wind Abrasion 61

3.2.1 Environmental Controls on the Wind Transport of Particles 62

3.3 Ventifacts 63

3.3.1 Morphology 64

3.3.2 Wind Abrasion Microfeatures 65

3.3.3 Ventifact Evolution 67

3.4 Yardangs 68

3.4.1 Yardang Morphology and Evolution 69

3.5 Hamadas and Stone Pavements 71

3.6 Deflation Basins and Pans 72

3.7 Discussion 73

3.7.1 Wind Erosion and Boundary Layer Climates 73

3.7.2 Reconstructing Past Wind Patterns from WindEroded Features 74

3.8 Conclusions 74

Acknowledgements 75

Further Reading 75

References 75

4 Dust: Sources, Entrainment, Transport81
Joanna Bullard and Matthew Baddock

4.1 Introduction 81

4.2 What Is Dust? 82

4.3 Production and Entrainment 83

4.4 Sources 85

4.5 Dust Events and Weather Systems 93

4.6 Dust in Suspension 98

Further Reading 100

References 100

5 Loess107
Helen M. Roberts

5.1 Introduction 107

5.2 Definitions of Loess and its Relationship to Dust 107

5.3 Distribution and Thickness of Loess Deposits 109

5.4 Loess Morphology 112

5.5 The Generation of Loess Sediments 114

5.5.1 The Glacial Model 116

5.5.2 The Desert Model 117

5.5.3 Seasonality and Continuity 118

5.6 Other Accumulations of Dust 119

5.6.1 Dust on the Ocean Floor 120

5.6.2 Ice Cores 120

5.7 The Palaeoclimatic and Palaeoenvironmental Records from Loess and Dust 121

5.8 Dating Loess and Dust Deposits 122

5.9 The Role of Dust in Climate Change 124

5.10 Cultural,Economic, and Environmental Significance of Loess and Dust 125

5.11 Conclusion 127

Further Reading 127

References 128

6 Desert Dunes: Form and Process133
Giles Wiggs

6.1 Introduction 133

6.2 The Classification of Dunes 134

6.2.1 Major Dune Types and Their Controls 135

6.3 Dune Dynamics 137

6.4 Dune Morphology 141

6.4.1 Barchan Dunes and Transverse Ridges 141

6.4.2 Linear Dunes 143

6.4.3 Star Dunes 145

6.5 Dune Orientation and Alignment 146

6.6 Dune Interactions and Equilibrium 148

6.6.1 Complex Systems Models 148

6.6.2 Analytical Models 150

6.7 Conclusion 151

Further Reading 151

References 151

7 Anchored Dunes157
Patrick A. Hesp and Thomas A.G. Smyth

7.1 Introduction 157

7.2 Nebkhas and Nebkha Fields 157

7.2.1 Generalities 157

7.2.2 Evolutionary Trends 159

7.3 Shadow Dunes 159

7.4 Foredunes 160

7.5 Lunette or Clay Dunes 162

7.6 Blowouts 163

7.7 Parabolic Dunes 165

7.8 Coastal Transgressive Sand Sheets and Dunefields 166

7.8.1 Semifixed (Stabilising) and Fixed (Stabilised) Desert Dunefields 166

7.9 Echo Dunes 168

7.10 Climbing,Clifftop, Falling, and Lee Dunes 170

7.11 The Influence of Topography on Wind Flow and Dune Orientation and Migration 172

7.12 Conclusion 172

Acknowledgements 172

Further Reading 172

References 172

8 Sand Seas179
Paul Hesse

8.1 Introduction 179

8.2 The Distribution of Sand Seas 180

8.3 Climatic Factors 181

8.3.1 Wind 181

8.3.2 Precipitation 182

8.4 Topography 186

8.5 Sorting Processes 189

8.6 Geological Factors 190

8.6.1 Lithology 190

8.6.2 Tectonic Setting 190

8.7 A Basin Model of SandSea Formation 192

8.8 Dune Patterns and Their Origins 195

8.8.1 Sediment Properties (Grain Size and Composition) 195

8.8.2 Climate Change and Changing Wind Regime 197

8.8.3 Sand Supply and Flow Paths 200

8.8.4 Climatic Gradients 200

8.9 Conclusion 200

Further Reading 204

References 204

9 Dune Sediments209
Charles Bristow and Ian Livingstone

9.1 Introduction 209

9.2 Dune Sands: Mineralogy, Shape, Surface Textures, and Colour 210

9.2.1 Mineralogy 210

9.2.2 Shape 212

9.2.3 Surface Textures 213

9.2.4 Colour 214

9.3 Particle Size Characteristics 216

9.3.1 Particle Size Patterns 219

9.4 Dune Structure 220

9.4.1 Sedimentary Structures in Sand Dunes 220

9.4.2 Bounding Surfaces 223

9.4.3 Sedimentary Models for Dunes and Interdunes 227

9.5 Eolianites 230

9.6 Conclusion 231

Further Reading 231

References 231

10 Dune Palaeoenvironments237
David S.G. Thomas

10.1 Introduction 237

10.2 A Date with Dunes 238

10.3 A Challenge: Inactive Versus Active Dunes 240

10.3.1 Vegetation 240

10.3.2 Interacting Environmental Controls 241

10.4 Complex Dune Development 245

10.4.1 Complex Dune Profile Records 246

10.5 Interpreting Dated Dune Records 247

10.6 A Schematic View of Interpreting Dune Palaeoenvironmental Records 249

10.6.1 Accumulation: A Better Way to Look at Dune Palaeoenvironmental Sequences? 250

10.7 Conclusion 254

Further Reading 254

References 254

11 Planetary Aeolian Geomorphology261
Mary C. Bourke, Matthew Balme, Stephen Lewis, Ralph D. Lorenz, and Eric Parteli

11.1 Introduction 261

11.2 Planetary Atmospheres 261

11.2.1 Mars 261

11.2.2 Titan 263

11.2.3 Venus 263

11.3 Planetary Sediment Transport (Mars, Titan, Venus) 263

11.3.1 Mars 264

11.3.2 Venus and Titan 266

11.4 From Sediment Transport to Aeolian Bedforms 266

11.4.1 Deriving Sediment Transport Characteristics from Planetary Bedform Characteristics 267

11.5 Planetary Aeolian Deposition Features: Dunes, Sand Seas, Sediment Source 269

11.5.1 Mars 269

11.5.2 Titan 270

11.5.3 Venus 272

11.6 Aeolian Dust 273

11.6.1 Dust in the Martian Atmosphere 273

11.6.2 Sources of Martian Dust 276

11.6.3 Landforms Associated with Aeolian Dust on Mars 276

11.7 Planetary WindEroded Landforms 278

11.7.1 Ventifacts 279

11.7.2 Yardangs 279

11.8 Conclusion 280

Further Reading 281

References 281

12 Application287
Andrew Warren

12.1 Introduction 287

12.2 Wind Erosion and Dust Production from Agricultural and Grazing Land 287

12.2.1 The Dust Bowl 287

12.2.2 FieldScale Application of Aeolian Research After the Dust Bowl 290

12.2.3 FieldScale Research into Wind Erosion in the Sahel of West Africa 290

12.2.4 Application at Expanding Scales 291

12.2.4.1 More Types of Land Use 291

12.2.4.2 New Sources of Information 292

12.2.4.3 Larger Scales Bring New EndUsers 293

12.2.4.4 Modelling 293

12.3 Shelter,Wind Erosion, and Dust Production: A Possible Confusion of Scale? 296

12.3.1 The Plains Shelterbelt 297

12.4 Blown Sand in the Desert 297

12.4.1 Oasis Agriculture 297

12.4.1.1 Contemporary Sand Fences 298

12.5 Blown Sand on the Coast 299

12.5.1 Blown Sand and Recreation 299

12.5.2 Coastal Protection 300

12.6 Conclusion: Learning from Past Mistakes 300

Notes 302

Further Reading 302

References 303

Index 307